js 10元買酒

10元買5瓶酒，2個蓋子換一瓶，4個瓶子換一瓶，最多換多少個。
下面貼代碼

function compute(yuan){
    var num = yuan/2; var jiu = num; var gai = num ; var ping = num ;var total = num;
    console.log(num,total)
    recompute();
    function recompute(){
        if(ping>=4 || gai>=2){
            total = total+parseInt(gai/2)+parseInt(ping/4);
            jiu = parseInt(gai/2)+parseInt(ping/4);
            gai = parseInt(gai%2) + jiu;
            ping = parseInt(ping%4) + jiu;
            console.log(total,jiu,gai,ping);
            recompute();
        }else{
            return false
        }   
    }
    return total;
}
compute(10);